Pregnant rabbits will be injected with alloxan on the 5th gestational day in order to produce experimental diabetes mellitus. The chronic effects of varying degrees of diabetes on the maternal, fetal and neonatal production of adrenal glucocorticoids will be studied. In addition, plasma steroid levels will be measured. Insulin replacement therapy will be provided for those animals having blood glucose greater than 300 mg/dl. In another group of animals, glucocorticoids will be given beginning on the 26th gestational day to determine whether or not fetal death and/or abortion can be prevented. The results of these studies will be compared to comparable controls to determine whether or not defects in the adrenal regulatory system can account, in part, for the high risk of these pregnancies.